There's seldom a transfer window where Stamford Bridge isn't one of the most intriguing locations to watch in terms of activity, with 2014 being no exception.

Jose Mourinho's side are something of an unknown quantity heading into January, with the club currently competing for top spot in the Premier League, but also disappointing at times in the first half of their season.

In any case, the Blues will always court a lot of transfer speculation at these times of the year, and it's here that we break down the latest news surrounding Chelsea's squad, as well as what it means for the club in the months to come.

After Villarreal's surprisingly positive start to the La Liga campaign, several stars in the Spanish club's roster have attracted a lot of winter attention, not least of whom is centre-back Mateo Musacchio.

However, the club are clearly in no selling mood, and have stated that any potential suitors must meet the defender's release clause of €50 million if they're hoping to prise him away from El Madrigal.

Musacchio has a contract until 2018, therefore he will be here for four more years. If someone wants to come and pay what he is worth, then we will talk.

For the player to leave, it depends on three parties, not just one or two—he has a contract. If he is wanted, then for Villarreal it is fine, but only if the money is paid up front.

The Spanish outfit currently sit sixth in La Liga and are enjoying one of their most successful runs of recent years, and so are understandably looking to hold onto their best talents in the hope of progressing further.

Musacchio may have been lined up as a replacement for John Terry, who is out of contract in the summer, but the Blues may now have to consider other options than the Argentinian international.

Michael Essien's eight-year stay at Stamford Bridge could reach its end in the New Year, it seems, after the midfielder's agent was quoted as saying that the situation could be sorted in the next 10 days.

He (Essien) could leave Chelsea this winter. Several major European clubs playing in the Champions League were informed and the situation should settle down within the next 10 days.

You should know that Michael was not on the list of players who can play in the Champions League with Chelsea, so he is free to play in the competition with another club.

As Piveteau states, his client is free to feature in any European competition after not finding a place on Chelsea's European squad, making him a rarely enticing prospect from one of England's biggest clubs.

Thorgan Hazard a Man in Demand

Following in the footsteps of his big brother, Thorgan Hazard is impressing on loan with Zulte Waregem and has suitors from Holland and his native Belgium vying for his services.

As Michiel Jongsma recently pointed out, the 20-year-old has just been named Jupiler Pro League Player of the Year, further increasing his profile:

According to Dutch sport website Voetbal International (h/t Sky Sports' Gerrit val Leeuwen), PSV were turned down in their most recent approach for the youngster, with the Eredivisie club's technical manager Marcel Brands noted as saying:

"He wants to stay in Belgium. So is he not attainable."

The article goes on to note that Chelsea's on-loan youngster could have already agreed to a deal with Anderlecht, the Belgian powerhouse responsible for shaping many a giant's career.